Circular knitting machines are fundamental equipments in the textile industry. They usually include a plurality of knitting needles on a needle dial and a cylinder to knit yarns of same or different materials to circular fabrics. The knitted fabrics are rolled into a bundle of flat cloth through a fabric rolling machine located below each circular knitting machine.
A conventional fabric rolling machine, such as U.S. Pat. No. 7,441,723, includes a frame, a transmission shaft hinged on the side walls of the frame, a displacement track defined by a lump and a stopper that are parallel with each other and a fabric rolling rod located in the displacement track and driven by the transmission shaft. When the fabric rolling machine is in operation the fabric rolling rod is driven by the transmission shaft to roll the fabric. The fabric rolling rod butts the transmission shaft through the fabric. During the rolling operation, the fabric with increasingly thickness butts the transmission shaft so that the fabric rolling rod is raised vertically in the displacement track. In order to keep the fabric in a flat and neat manner during the rolling operation the fabric rolling rod further has a fabric guiding rod set to draw and stretch the fabric, and also to direct movement of the fabric and provide a tension to the fabric. At the initial fabric rolling stage the fabric rolling rod is driven by the transmission axle and revolves. When the total weight of the fabric rolling rod and fabric is less than the fabric tension the fabric rolling rod is drawn and revolves in a direction opposite to the transmission axle. With gradually increase of the fabric rolled on the fabric rolling rod the total weight of the fabric rolling rod and fabric also increases gradually. The force pressed on the transmission axle below also increases. When the total weight of the fabric rolling rod and fabric is greater than the fabric tension the fabric rolling rod is driven merely by the transmission axle in the same direction thereof; i.e., at the initial stage the rolled fabric is knitted at a greater yarn density and also in a greater thickness, but at the later stage the rolled fabric is knitted at a lower yarn density and in smaller thickness. As a result, a portion of the fabric in the entire roll of fabric does not meet requirement of quality, and it is waste of the fabric knitted by the circular knitting machine.
R.O.C. patent No. 558573 also discloses another type of fabric rolling machine which comprises a machine body, a sub-box, a speed change box and a fabric spreading rack. The machine body has two side boxes and three fabric guiding rods hinged between them at varying heights in a staggered manner. Two bracing rods are provided at the tope end of the side boxes, and a fabric rolling rod is provided at the front end of the side boxes. The fabric rolling rod is movably located in a preset guide track in the side boxes and driven by the fabric guiding rods to rotate. The guide track is inclined and extended against the side boxes. The fabric rolling rod moves in an inclined direction in the guide track with increasing of the rolled fabric. Although the fabric guiding rod is not located directly beneath the guide track, namely, the fabric guiding rod does not bear the total weight of the fabric rolling rod and fabric rolled thereon, but a component force of the total weight according to the inclined angle of the guide track. However, as the fabric rolled on the fabric rolling rod increases gradually the component force of the fabric rolling rod and fabric pressed on the fabric guiding rods also increases; finally, it still happens that the fabric rolled at the initial stage has a greater yarn density and a greater thickness while the fabric rolled at the later stage has a smaller yarn density and a smaller thickness.